Under the 3GPP standards, a NodeB (or an eNB in LTE) is the base station via which mobile devices connect to the core network. Recently the 3GPP standards body has adopted an official architecture and started work on a new standard for home base stations (HNB). Where the home base station is operating in accordance with the LTE standard, the HNB is sometimes referred to as a HeNB. A similar architecture will also be applied in the WiMAX network. In this case, the home base station is commonly referred to as a femto cell. For simplicity, the present application will use the term HNB to refer to any such home base station. The HNB will provide radio coverage (3G/4G/WiMAX) within the home and will connect to the core network via a suitable public network (for example via an ADSL link to the Internet) and in the case of the 3GPP standards, via an optional HNB gateway (HNB-GW).
An HNB will operate on the same or on a different frequency to the macro cell(s) within which it is located and on the same or a different frequency to other HNBs operating in its vicinity. Under current proposals, the operating radio parameters (such as its frequency and/or its primary scrambling code (PSC)) of the HNB are either acquired from the core network operator when the HNB is powered up or are acquired through a self configuration routine that involves learning the surrounding environment, and the only way that these parameters can be changed is by resetting or rebooting the HNB. It is expected that HNBs will be widely deployed. For example, provision has been given in 3GPP TS 22.011 to address 125 million HNBs within a PLMN (Public Land Mobile Network). The inventors have realized that with such a wide spread deployment, radio conditions around the HNB may change regularly resulting in varying levels of interference.